The invention relates to a multiaxis robot with at least one gear associated with a robot axis and having a gearbox with circumferentially placeable retaining strips for fixing control cams for monitoring the swivel angle of the robot axis.
For monitoring and/or adjusting a permitted swivel angle of individual robot axes adapted to the given movement conditions of the robot, it is known to place on a robot part, such as the rocker arm, control cams following the gear circumference and which monitor the operating range of the robot corresponding to the desired swivel angle. For the circumferential, rotary fixing of the control cams use is generally made of retaining strips, which are screwed to the circumference of the robot axis. In order to ensure the small tolerances necessary for a satisfactory operation of the robot, the surfaces for fixing the retaining strips must be worked, e.g. hardened, ground, turned, milled and/or profiled. In the case of multiaxis industrial robots, which have a caroussel swivellable about a basic axis (A1 axis) and placed on a frame and a robot arm swivellable about several axes and placed on a rocker arm on the caroussel, the retaining strips for fixing the control cams for monitoring the swivel angle of the A1 axis are e.g. placed on the circumference of a slewing ring of the caroussel.
In the case of radial screwing of the retaining strips to the circumference of the gearbox on the one hand the handling for fitting and removing the retaining strips is complicated and on the other the rotational accuracy of the grooved or retaining strip is limited.
In the case of a robot of the aforementioned type and whilst avoiding the aforementioned disadvantages, the problem of the invention is to propose a connection between the retaining strips for fixing the control cams and the robot, which ensures the best possible rotational accuracy of the retaining strips and requires a limited amount of space.
In the case of a robot of the aforementioned type, the invention solves this problem in that the retaining strips have a substantially arcuate construction with an inner circumference roughly corresponding to the outer circumference of the gearbox and in that the retaining strips are frontally braceable against one another for fixing to the gearbox.
The construction according to the invention permits a simple and rapid direct fitting of the arcuate retaining strips to the circumference of the gearbox by bracing the same on the gearbox.
As a result of the invention a more precise positioning of the grooved strips is possible in a simpler and faster way than is the case in the prior art.
In a preferred embodiment, bracing is brought about in that in the vicinity of their ends the retaining strips have in each case an axial hole receiving a retaining pin, each retaining pin being radially traversed by at least one hole serving to receive a locking screw passing through the holes of the retaining pins of two adjacent retaining strips for the purpose of bracing the retaining strips on the gearbox. In this way the circumferential bracing of the retaining strips on the gearbox can be adjusted by means of the locking screws.
Appropriately the retaining pins are traversed by in each case two holes receiving a locking screw and preferably at least one of the holes, traversed by the locking screw, of the retaining pins of two adjacent retaining strips is a tapped hole in whose thread engages the associated locking screw.
In a preferred development the retaining strips can be circumferentially fixed to the gearbox by the retaining pins passing at least on one side out of the axial holes of the retaining strips and e.g. a head of the retaining pins passing out of the axial holes of the retaining strips can be engaged in a shaped recess to which the gear is secured or strongly connected to the gearbox.
The retaining strips are preferably constructed in per se known manner as grooved strips with externally circumferentially positioned webs and grooves for fixing the control cams, the webs of the grooved strips in particular having a substantially T-shaped profile.
Appropriately there are two arcuate retaining strips substantially completely engaging round the gearbox and which span the latter by in each case 180xc2x0.
According to a preferred development the inner circumference of the retaining strips has a complimentary profile to a retaining profile located on the outer circumference of the gearbox for the positive bracing of the retaining strips on the gearbox.
The profile of the retaining strips complimentary to the retaining profile of the gearbox ensures an axial positive engagement, so that during bracing the parts are precisely positioned. As a result of the circumferential bracing and the symmetrical arrangement a maximum possible rotational accuracy of the grooved strips is ensured.
In a preferred development, the retaining profile of the gearbox has at least one circumferential collar and the profile of the retaining strips at least one circumferential groove complimentary thereto, or the retaining profile of the gearbox has at least one circumferential groove and the profile of the retaining strips at least one circumferential collar complimentary thereto. For the construction of the retaining profile on the gearbox, which is generally constructed as a lathe tool part, it is consequently merely necessary to carry out a simple, cost-effective, e.g. cutting operation.